Support disabling NoteDb reads for tests

In I0a9eb0ad we fixed a NoteDb-specific issue where loading the
default search results page caused ChangeNotes to get loaded, despite
not causing changes to load from ReviewDb.

Support this configuration in tests by adding a method to
NotesMigration that is called in AbstractChangeNotes#load(). In
production this method always returns false so the cost is negligible.

Change-Id: I22622cb3c834eeb1391d5b80247beafe36fffedf

gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/AbstractDaemonTest.java

@@ -529,6 +529,16 @@ public abstract class AbstractDaemonTest {
         atrScope.newContext(reviewDbProvider, null, anonymousUser.get()));
   }
 
+  protected Context disableDb() {
+    notesMigration.setFailOnLoad(true);
+    return atrScope.disableDb();
+  }
+
+  protected void enableDb(Context preDisableContext) {
+    notesMigration.setFailOnLoad(false);
+    atrScope.set(preDisableContext);
+  }
+
   protected static Gson newGson() {
     return OutputFormat.JSON_COMPACT.newGson();
   }

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/change/ChangeIT.java

@@ -31,6 +31,7 @@ import com.google.common.base.Function;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.AcceptanceTestRequestScope;
 import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.TestProjectInput;
@@ -983,16 +984,20 @@ public class ChangeIT extends AbstractDaemonTest {
     createChange();
 
     setApiUserAnonymous(); // Identified user may async get stars from DB.
-    atrScope.disableDb();
-    assertThat(gApi.changes().query()
-          .withQuery(
-            "project:{" + project.get() + "} (status:open OR status:closed)")
-          // Options should match defaults in AccountDashboardScreen.
-          .withOption(ListChangesOption.LABELS)
-          .withOption(ListChangesOption.DETAILED_ACCOUNTS)
-          .withOption(ListChangesOption.REVIEWED)
-          .get())
-        .hasSize(2);
+    AcceptanceTestRequestScope.Context ctx = disableDb();
+    try {
+      assertThat(gApi.changes().query()
+            .withQuery(
+              "project:{" + project.get() + "} (status:open OR status:closed)")
+            // Options should match defaults in AccountDashboardScreen.
+            .withOption(ListChangesOption.LABELS)
+            .withOption(ListChangesOption.DETAILED_ACCOUNTS)
+            .withOption(ListChangesOption.REVIEWED)
+            .get())
+          .hasSize(2);
+    } finally {
+      enableDb(ctx);
+    }
   }
 
   @Test

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/git/VisibleRefFilterIT.java

@@ -18,6 +18,7 @@ import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
 
 import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.AcceptanceTestRequestScope;
 import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.common.data.AccessSection;
@@ -77,7 +78,6 @@ public class VisibleRefFilterIT extends AbstractDaemonTest {
         .getGroupUUID();
     setUpPermissions();
     setUpChanges();
-    atrScope.disableDb();
   }
 
   private void setUpPermissions() throws Exception {
@@ -269,6 +269,7 @@ public class VisibleRefFilterIT extends AbstractDaemonTest {
       }
     }
 
+    AcceptanceTestRequestScope.Context ctx = disableDb();
     try (Repository repo = repoManager.openRepository(project)) {
       ProjectControl ctl = projectControlFactory.controlFor(project,
           identifiedUserFactory.create(Providers.of(db), user.getId()));
@@ -277,6 +278,8 @@ public class VisibleRefFilterIT extends AbstractDaemonTest {
       Map<String, Ref> all = repo.getAllRefs();
       assertThat(filter.filter(all, false).keySet())
           .containsExactlyElementsIn(expected);
+    } finally {
+      enableDb(ctx);
     }
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/notedb/AbstractChangeNotes.java

@@ -124,6 +124,9 @@ public abstract class AbstractChangeNotes<T> {
       loadDefaults();
       return self();
     }
+    if (args.migration.failOnLoad()) {
+      throw new OrmException("Reading from NoteDb is disabled");
+    }
     try (Timer1.Context timer = args.metrics.readLatency.start(CHANGES);
         Repository repo = args.repoManager.openRepository(getProjectName());
         LoadHandle handle = openHandle(repo)) {

gerrit-server/src/main/java/com/google/gerrit/server/notedb/NotesMigration.java

@@ -42,6 +42,15 @@ public abstract class NotesMigration {
 
   public abstract boolean writeAccounts();
 
+  /**
+   * Whether to fail when reading any data from NoteDb.
+   * <p>
+   * Used in conjunction with {@link #readChanges()} for tests.
+   */
+  public boolean failOnLoad() {
+    return false;
+  }
+
   public boolean enabled() {
     return writeChanges() || readChanges()
         || writeAccounts() || readAccounts();

gerrit-server/src/test/java/com/google/gerrit/testutil/TestNotesMigration.java

@@ -22,6 +22,7 @@ import com.google.inject.Singleton;
 public class TestNotesMigration extends NotesMigration {
   private volatile boolean readChanges;
   private volatile boolean writeChanges;
+  private volatile boolean failOnLoad;
 
   @Override
   public boolean readChanges() {
@@ -43,6 +44,11 @@ public class TestNotesMigration extends NotesMigration {
     return false;
   }
 
+  @Override
+  public boolean failOnLoad() {
+    return failOnLoad;
+  }
+
   public TestNotesMigration setReadChanges(boolean readChanges) {
     this.readChanges = readChanges;
     return this;
@@ -53,6 +59,11 @@ public class TestNotesMigration extends NotesMigration {
     return this;
   }
 
+  public TestNotesMigration setFailOnLoad(boolean failOnLoad) {
+    this.failOnLoad = failOnLoad;
+    return this;
+  }
+
   public TestNotesMigration setAllEnabled(boolean enabled) {
     return setReadChanges(enabled).setWriteChanges(enabled);
   }